Power supply



FIG. 1 is a perspective view of a power supply showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof; and,

FIG. 6 is a top plan view thereof.

The bottom plan view of the current new design is omitted as no features in the bottom view is considered to be claimed for the current new design. 

The ornamental design for a power supply, as shown and described. 